The present invention relates to electronic components having multiple circuit board, and more particularly, to a high density electronics package having a plurality of stacked circuit boards that are heat-sinked to the housing.
A common method of mounting cylindrical circuit boards in electronic housings is by using screws and standoffs. This method of mounting circuit boards requires areas on the circuit boards to be kept clear of components and circuitry, thus reducing the usable area of the boards. Multiple stacks of circuit boards using standoffs require close tolerance of screw holes, spacers, and circuit card/heat sink thicknesses. If this is not the case, the ending tolerance stack-up prevents a proper fit and alignment within the housing. Current cylindrical housings and circuit boards are generally mounted together using conventional screw fasteners and standoffs. This method makes the electronics package difficult to assemble, provides poor vibration resistance and makes thermal management difficult.
When a thermal path to an electronic housing is needed, it often requires the design and installation of elaborate devices to accomplish this. The drawbacks of such thermal path hardware are a minimal thermal path and relatively weak structural integrity. To obtain structural stiffness, a large quantity of screws and standoffs or stiffeners are required, since support is generally furnished only in small areas where the diameter of the standoffs contact the circuit boards. The use of lightweight "touch" type connectors (woe strips, fuzz buttons, etc.) are difficult to employ in this type of design due to the inherent lack of positioning capability. Distortion of circuit boards by use of screw fasteners may cause gaps between the contacts, thus creating board malfunctions.
Therefore, it is an objective of the present invention to provide for a high density electronics unit having a plurality of stacked circuit boards that is structurally strong and has sufficient heat sinking.